Development and evaluation of a formaldehyde-stabilized tuberculin as a safe and potent alternative to phenol-based purified protein derivative for the diagnosis of animal tuberculosis

Replacing phenol with 3% formaldehyde significantly enhanced the sensitivity, stability, and biosafety of tuberculin without compromising specificity. The new formulation eliminates phenol toxicity while improving diagnostic yield in animal TB screening. These findings support the integration of formaldehyde-stabilized tuberculin into national and international diagnostic standards as a reliable and safer alternative for large-scale veterinary applications.